-Acute respiratory distress syndrome, or ARDS,
is a life-threatening lung injury
that results in dangerously low levels of oxygen in the blood,
also known as hypoxemia.
ARDS has been a known symptom of pneumonia, influenza,
and now COVID-19.
-When COVID first started,
the paradigm that we had become so used to treating --
severe infection-related hypoxemia was ARDS.
In ARDS, the impairment often is in the alveoli
or in the interstitium, or the spongy part of the lung.
The alveoli are the small air sacs
that gas exchange occurs across,
both oxygen going onto the blood and carbon dioxide
getting off-loaded for us to breathe out.
And if it's significant enough, then gas, oxygen in particular,
is difficult to diffuse across airways --
alveoli, interstitium -- to the blood vessels.
This leads to low levels of blood oxygen, or hypoxemia,
that can have severe impact
on multiple organs throughout the body.
-The extent of the damage caused by ARDS in COVID-19 patients
can most effectively be seen when comparing x-rays
and CT scans of their lungs.
-The areas that the lung are represented by the darker areas,
because that's air-filled spaces that show up black
on the chest x-ray.
In the center there, you see the heart,
opacified in white in the middle.
But around it should be surrounded
by darker lung tissue.
And you can see that in the edges of the lung,
in particular on the right side of the image,
in the middle of the lung field, there's extra areas of white.
And those areas are due to injury and scarring
within the air spaces, within the alveoli.
On the CAT scan, we'll see similar findings.
Their heart should be in the center
and is that whiter, more opacified area.
And it should be surrounded by dark grey material,
dark grey to dark material, which is the lung.
This CT scan, CAT scan of the lung is significantly abnormal
because there is diffuse abnormalities,
and you can see dense consolidations
that you don't necessarily
make dark air spaces evident through them.
-COVID-19 ARDS is unique in that it can also damage
the patient's blood vessels,
while promoting significant blood clotting.
-We, ourselves, when examining patients using ultrasound,
modalities,
and CAT scans, found a good number of clot,
either traveling through the heart
on the way to the lungs or within the lungs.
Not only is the alveolar surface and the spongy interstitium
part of the lung damaged by the infection,
but now there is an impairment on the other side,
the blood vessels --
both direct injury to the blood vessels and clot
within the blood vessels.
-This one-two punch of ARDS and clotting multiplies
the likelihood of severe hypoxemia
while also leading to possible organ failure
or the patient suffering a stroke.
-The chronicity of this is unknown.
For those patients that come into the hospital
with significant enough COVID,
and especially for those patients that come into the ICU
and need a ventilator,
it is very likely that they may have more permanent damage.
What we do know is based on the experience with SARS-CoV 1,
the initial SARS syndrome,
and those patients that have severe influenza syndromes
such as the avian flu from years past,
that when people have looked at those patients
that have come through the ICU and/or been on the ventilator
that many of them, if not the majority of them,
will have abnormalities that you can still pick up on imaging,
via chest x-ray or CAT scan.
And the other scary issue with this novel virus
is the potential that beyond the lung,
there may be impact to other organs that's long-lasting,
in particular skin soft tissue and nerves and brain.
And we just don't know the full impact down the road.